Dispersion lance and shield for dispersing a treating agent into a fluid stream

ABSTRACT

A dispersion apparatus for dispersing a treating agent into a fluid treatment system that includes a flow duct in which a fluid stream flowing through the duct is mixed with the treating agent. The apparatus is based on a multi-pipe lance positioned in the stream flow, where each pipe supplies a minimum of feed discharge nozzles (typically one to four), and the individual pipes branch off from the same location. Use of the multi-pipe lance, in combination with a suitable baffle, results in better overall dispersion/distribution of the injected medium by surface area. By improving the surface area distribution, better utilization of the injected sorbent can be achieved. The baffle acts to generate a low pressure zone on its downstream side and creates a high-intensity turbulence plume in the fluid. The orifices of the pipe are located to inject the treating agent into the turbulence plume to better distribute and intermix the injected treating agent into the surrounding fluid.

RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/152,654, filed May 15, 2008. The latter claimed priorityfrom U.S. Provisional Patent Application No. 60/930,703 filed May 18,2007.

FIELD OF INVENTION

This invention relates generally to apparatus and methods for fluidtreatment, and more specifically relates to apparatus for injecting atreating agent into a fluid stream while generating enhanced fluid phaseturbulence to better distribute and intermix the injected treating agentinto the surrounding fluid.

BACKGROUND OF INVENTION

During the course of treating an acid or other gas, in order for exampleto control the atmospheric emission of polluting contaminants such assulfur oxides, it is common as one step of the process to disperse solidparticles of a treating agent such as a carbonate into the gas in orderto react with or adsorb the undesired component. In order to do this adispersion lance or other device or collection of devices may be used,the function of which is to disperse the solid particles of treatingagent into the gaseous stream. Nozzles or collections of particleejection nozzles can be used for this purpose. Since, however, simpleejection of the particles from such nozzles is not very effective ingenerating thorough mixing of the particles with the gas stream, it isalso known to use baffles, usually positioned directly downstream of theinjection point to encourage turbulence, thereby enhancing the mixing ofparticles with the gas stream. These prior devices and apparatusarrangements, however, have been of only limited efficacy, often becausethe turbulence generated has not been effective enough to break up theejected particle streams, which to the contrary are commonly found, whenexamined, to advance from their injection points as rather distinctlinear streams as they move into the surrounding ambient gas stream.Accordingly, a need has existed for an injection lance and baffleconstruction which is fully able to produce the highly turbulentconditions required for full and effective dispersion and mixing intothe gas stream of the injected particles of the treating agent.

Similar considerations as described above for the case of injection ofsolid particles into a gas flow, arise where an injection lance andbaffle construction is used for injecting liquids or gaseous treatingagents into a fluid flow of a gas, or injection of solid particles,liquids, or gases into a flow of a liquid phase. Such injection can, ofcourse, be for other well-known purposes, i.e. not necessarily foreliminating or reducing contaminating sulfurous and/or other noxiouscomponents from flue gases or the like.

In our aforementioned Ser. No. 12/152,654 (hereinafter referred to as'654) application, apparatus is disclosed which is capable ofconsiderably alleviating the cited difficulties of the prior art.Specifically, a dispersion lance is provided for use in combination witha fluid treatment system of the type which includes a flow duct in whicha fluid stream is mixed with a treating agent. The dispersion lanceincludes a pipe mounted in the duct with its axis approximatelytransverse to the direction of the fluid stream flow, the pipe having aseries of openings along its length for injecting a treating agentsupplied to the pipe into the fluid stream. A baffle extends lengthwisealong the pipe, the baffle having a cross-section the central portion ofwhich is V-shaped, with the apex of the V facing upstream of the fluidstream flow, and with generally flattened wing portions extending fromthe legs of the V beyond the sides of the pipe in a direction where theytransversely intersect the stream flow. The baffle acts to generate alow pressure zone on its downstream side, which enhances turbulence inthe fluid. The orifices of the pipe are located to inject the treatingagent into the low pressure zone to better distribute and intermix theinjected treating agent into the surrounding fluid.

The wings of the baffle form an angle of less than 180° with respect tothe legs of the central portion, and the apex of the central portion Vgenerally subtend an angle of from about 30 to 135°, with an angle ofabout 90° being typical. The wings can have a generally rectangularshape, and may be provided with notches on their trailing edge.

In a typical application as will be described below, the invention isapplicable to the case of injection of solid particles into a gas flow.A particularly valuable such use is found in the aforementioned processof dispersing solid particles of a sorbent treating agent such as acarbonate into a flue gas in order to react with or adsorb a componentof the gas to avoid its discharge into the environment, and/or torecover the component for other uses. In the following, this particularuse of the invention will be emphasized. However, it will be appreciatedthat the invention is also applicable to the environments where aninjection lance and baffle construction is to be used for injectingliquids or gaseous treating agents into a gaseous flow; or where aninjection lance and baffle construction is to be used for injection ofsolid particles, or liquids or gases, into a flow of a liquid phase.

SUMMARY OF INVENTION

Although the lance construction in our '654 application results in muchimproved mixing relative to the prior art lance, the overalldistribution of the surface area of the injected treating agent (such asthe exemplary sorbent) was found to not be markedly uniform along thelength of the lance. Through further analysis of the solids dispersionof the '654 lance, the present inventors discovered that the mass andthe surface area of the particles emitted from the lance were biasedtowards its far end (due to the momentum of the particles). This is aproblem that calls for solution, in that for mass-transfer-limitedreactions, the removal efficiency of an injected sorbent is a functionof the distribution of surface area of the injected sorbent in thegas-carrying duct.

To address this issue, we have now developed a multi-pipe lance, whereeach pipe supplies a minimum of feed discharge nozzles (typically one tofour), and the individual pipes branch off from the same location or areotherwise fed with the sorbent or other treating agent to be dispersed.We have found that use of the multi-pipe lance in combination with asuitable baffle, results in better overall dispersion/distribution ofthe injected medium by surface area. By improving the surface areadistribution, better utilization of the injected sorbent can be achieved

The multi-pipe lance retains the bulk, in-duct mixing properties of the'654 lance, and improves the distribution of surface area of theinjected sorbent along the length of the lance. The improved surfacearea distribution is accomplished through the use of a dispersion lancemounted in the gas-carrying duct with its axis approximately transverseto the direction of the fluid stream flow, the lance having a treatingagent feed section, and a plurality of parallel pipes extending fromsaid section, each said pipe having one or more feed discharge nozzlesalong its length for injecting the treating agent supplied to said pipeinto the fluid stream. A baffle extends lengthwise along the upstreamside of the lance, the baffle preferably being formed as a partialcylindrical surface, such as the surface of a semi-cylinder. The convexside of the cylindrical surface faces upstream of the fluid stream flow,and adjoins generally flattened wing portions which extend from thelateral edges of the cylindrical surface to beyond the lateral sides ofthe multiple pipes, where the wings transversely intersect the streamflow. The baffle acts to generate a low pressure zone on the downstreamsides of the nozzle-feed pipes, which enhances turbulence in the gas.The feed discharge nozzles of the nozzle-feed pipes are located toinject the treating agent into the low pressure zone to betterdistribute and intermix the injected treating agent into the surroundinggas stream.

The said treating agent feed section receives feed from an inlet supplyline, and includes successively in the downstream direction: a venturisection, a mixing bar section, and a feed splitter section. The venturisection redirects sorbent particles away from the walls of the main feedpipe downstream of any bends in the inlet supply line. This feature isdesirable when the supply of sorbent to the lance is not uniform, whichit usually will not be, and has the intended purpose of improving theperformance of the mixing bar section.

The mixing bar section serves to spread the sorbent particles uniformlyacross the main feed pipe cross-section in preparation for the splittervane section. The feed splitter section allocates the uniformlydistributed sorbent particles evenly into separate compartments each ofwhich leads into one of the separate nozzle-feed pipes. The nozzle-feedpipes transfer the uniformly allocated sorbent particles to thedischarge nozzles. There can be one or more discharge nozzles per feedpipe, though the number is preferably limited to the minimal required toachieve the desired spray coverage. Each discharge nozzle has an orificeopening size sufficiently small to balance the pressure drop evenlyacross the separate feed pipes. This serves to ensure that the pneumaticair and sorbent particles it is conveying are allocated relativelyevenly between the separate feed pipes. The numbers of discharge nozzlesper pipe, as well as the distance between nozzles on a single pipe, areboth limited in order to minimize the bias in the mass flow rate andtotal surface area of solids emitted from each nozzle. The distributionof injected sorbent particles along the length of the lance can bemodified to match any potential uneven distribution of gas flow alongthe length of the lance by adjusting the nozzle orifice opening sizes ofindividual nozzles and by adjusting the positions of the nozzles alongthe length of the lance.

The baffle preferably extends below the last nozzle for a distanceapproximately equal to the distance between successive dischargenozzles. Due to the flue gas flow patterns in the wake of the baffle,the excess length of the baffle (past the last nozzle) serves todistribute additional sorbent beyond the last discharge nozzle.

BRIEF DESCRIPTION OF DRAWINGS

The invention is diagrammatically illustrated, by way of example, in thedrawings appended hereto, in which:

FIGS. 1 and 1A are respectively schematic transverse and plan sectionalviews of a typical prior art dispersion lance, which is positioned in aduct carrying a gas stream, which is being treated with a particulateinjected from the lance;

FIGS. 2 and 2A are respectively schematic transverse and plan sectionalviews of a dispersion lance and baffle in accordance with the inventionof our '654 application, which are positioned in a duct carrying a gasstream which is being treated with a particulate injected from thelance;

FIG. 3 is a schematic partially broken-away perspective view of amulti-pipe dispersion lance and baffle in accordance with the invention;

FIG. 4 is an enlarged view of the upper portions of the FIG. 3apparatus;

FIG. 5 is a side elevational view of the lance and baffle apparatus ofFIGS. 3 and 4;

FIG. 6 is a front elevational view of the lance and baffle apparatus ofFIGS. 3 and 4, looking at the apparatus from downstream of same;

FIG. 7 is a top plan view, schematic and partially broken away, of thelance and baffle apparatus of FIGS. 3 and 4;

FIG. 8 is a schematic broken-away perspective view showing typicalinjected sorbent particle tracks enabled by a pair of the prior artapparatus of FIGS. 1 and 1A;

FIG. 9 is a schematic broken-away perspective view showing typicalinjected sorbent particle tracks enabled by a pair of multi-pipe lanceand baffle dispersion apparatus of the type shown in FIGS. 3 through 7;

FIG. 10 is a schematic top plan view illustrating the injected sorbentparticle tracks for the prior art lance of FIGS. 1 and 1A;

FIG. 11 is a schematic top plan view illustrating the injected sorbentparticle tracks for the apparatus of the invention shown in FIGS. 3through 7;

FIGS. 12A through 12F schematically depict cross-sectional views taken10 ft downstream of the injection plane for the prior art lance of FIGS.1 and 1A, and show distribution and mixing of the injected sorbentparticle surface area by particle size at the said downstream position;

FIGS. 13A through 13F schematically depict cross-sectional views taken10 ft downstream of the injection plane for the apparatus of theinvention as in FIGS. 3 through 7, and show the distribution and mixingof the injected sorbent particle surface area by particle size at thesaid downstream position;

FIGS. 14A and 14B schematically depict cross-sectional views taken 10 ftdownstream from the prior art lance of FIGS. 1 and 1A, and from themulti-pipe lance of the invention as in FIGS. 3 through 7, and show foreach the total distribution and mixing of injected sorbent particlesurface area for all particle sizes at the said downstream position; and

FIG. 15 is a graph depicting the normalized pneumatic air and sorbentsurface area distribution along the length of lance for a prior artlance as in FIGS. 1 and 1A, and for the multi-pipe lance and baffleapparatus of the invention as in FIGS. 3 through 7.

DESCRIPTION OF PREFERRED EMBODIMENT

In FIGS. 1 and 1A schematic transverse and plan sectional views of atypical prior art dispersion lance 10, which is positioned in a duct 12carrying a gas stream flow 14 which is being treated with a particulateejected from the lance. The position of the lance within duct 12 is notshown to scale; rather the duct 12 and its actual wall spacing fromlance 10 is merely intended to be suggested by the dotted lines usedhere—and as well in FIG. 2A. Also while dimensions and certain anglesare shown in FIGS. 1, 1A, 2 and 2A, these are cited for illustrationonly and are not in any way intended to be limiting of the invention.The lance 10 comprises a pipe 8 which is mounted in duct 12 by means notshown. Pipe 8 has two parallel lines of openings 16 along its length. Asseen in FIG. 1A the parallel lines of openings 16 are at the downstreamfacing side of pipe 8, and are oriented so that axial openings inopposed lines are at an angle of about 90° with respect to each other.The particulate treating agent to be dispersed into the flowing gasstream 14 is provided to pipe 8 and the particles are then injected intothe gas stream from openings 16. A pressurized carrier gas can beprovided to pipe 8 with the particles to enable their ejection, or othermeans can be used to generate forces for ejection of the particlesthrough openings 16.

In FIGS. 2 and 2A schematic transverse and plan sectional views appearof a dispersion lance and baffle in accordance with the '654 invention,which are similarly positioned in a duct 12 carrying a gas stream whichis being treated with a particulate ejected from the lance. The pipe 18is substantially similar to pipe 8 of FIGS. 1 and 1A, and is againprovided with openings or orifices 20 arranged along two parallel linesextending along pipe 18. However unlike the prior art device, pipe 18 isassociated with a baffle 22, which is mounted in any convenient mannerin duct 12, including by being affixed to pipe 18 by supports 24. Pipe18 and baffle 22 can be positioned in a vertical or horizontalorientation in duct 12, or otherwise depending on requirements and onduct geometry. Baffle 22 extends lengthwise along pipe 18, and has across-section the central portion 26 of which is V-shaped, with the apex28 of the V facing upstream of the gas stream flow 14, and withgenerally flattened wing portions 30 extending from the legs 32 of the Vbeyond the lateral sides of pipe 18 in a direction where theytransversely intersect the gas stream flow 14. The apex 28 of the Vsubtends an angle of about 90°, but more generally can be in the rangeof from about 30 to 135°. The V shape of the central portion 26 ofbaffle 22 can be modified so as to be rounded at its bottom to a concavecurve (i.e. at the surface facing pipe 18), or even to the extent ofdefining a U shape as it partially encloses pipe 18. Wing portions 30are seen to define a second V 34 with the legs 32. The included angle ofsecond V 34 should be less than 180°. Wing portions 30 are typicallyflat rectangles as seen in FIG. 2, but they can also be modified, as forexample by being provided with notches of various shapes on theirtrailing edges.

FIGS. 3 through 7 depict in simplified views the improved multi-pipedispersion lance 40 and baffle 72 of the invention. FIGS. 3 through 7are best considered simultaneously. Although the present invention isnot in any way to be considered so limited, for purposes of concreteexemplification, the dispersion apparatus will be discussed especiallyin the case where it is being used for dispersing a sorbent treatingagent into a flowing stream of flue gas in a duct such as has beendescribed in connection with FIGS. 2 and 2A.

The lance 40 comprises a main feed inlet pipe 42, which receives theparticulate treating agent such as calcium carbonate at inlet end 44where it is carried by a pneumatic air or other gas flow. The treatingagent feed section 45 receives the feed from inlet pipe 42, and includessuccessively in the downstream direction: a venturi section 46, a mixingbar section 48, and a feed splitter section 50. The feed thus passessuccessively through venturi section 46, then through mixing bar section48, and to feed splitter section 50 which allocates the feed into theseparate nozzle-feed pipes 52 which extend downwardly in parallelfashion. Four such feed pipes 54, 56, 58, and 60 are shown, butdifferent pluralities of nozzle-feed pipes may be used consistent withneeds of a given system.

The venturi section 46 redirects sorbent particles away from the wallsof main feed pipe 42 downstream of any bends in the inlet supply line.This feature is desirable when the supply of sorbent to the lance is notuniform, which it usually will not be, and has the intended purpose ofimproving the performance of the mixing bar section 48.

The mixing bar section 48 includes a series of vertically spaced plates49 each including spaced bars 51. Section 48 serves to spread thesorbent particles uniformly across the main feed pipe cross section inpreparation for the feed splitter section 50. Section 50 includes anenlarged cylinder 62 in which is mounted splitter vanes 64 which alsoextend into the diametrically larger cylinder 66. The vanes 64 dividethe section 50 into four compartments 68 (FIG. 7), each of whichconnects to one of the nozzle feed pipes 52. The splitter section 50allocates the uniformly distributed sorbent particles evenly intocompartments 68. The nozzle-feed pipes 52 transfer the uniformlyallocated sorbent particles to the discharge nozzles 70 which arepresent along each of the nozzle-feed pipes. There can be one or moredischarge nozzles per feed pipe, though the number is preferably limitedto the minimal required to achieve the desired spray coverage. Eachdischarge nozzle 70 has an orifice opening size sufficiently small tobalance the pressure drop evenly across the separate feed pipes. Thisserves to ensure that the pneumatic air and sorbent particles it isconveying are allocated relatively evenly between the separate feedpipes and nozzles. The number of discharge nozzles 70 per pipe, as wellas the distance between nozzles on a single pipe, are both limited inorder to minimize the bias in the mass flow rate and total surface areaof solids emitted from each nozzle.

It will be seen from FIGS. 3, 5, and 6 that the separate nozzle-feedpipes 52 terminate at differing distances below the compartments 68, andthat accordingly the nozzles 70 of each said pipe are at a portion of agiven pipe where the nozzle discharges are not impeded by any of theremaining pipes.

A baffle 72 extends lengthwise along the upstream side of lance 40.Although the baffle can incorporate the V shape configuration of thebaffle in FIGS. 2 and 2A, or a modification in which the V is rounded toa curve at its vertex, it has been found preferable for the baffle to beformed as a partial cylindrical surface 74 (FIG. 7), here as the surfaceof a semi-cylinder. The concave side of cylindrical surface 74 facesupstream of the fluid stream flow, and adjoins generally flattened wingportions 76 which extend from the lateral edges of the cylindricalsurface to beyond the lateral sides of the multiple pipes, where thewings transversely intersect the stream flow. The baffle 72 acts togenerate a low pressure zone on the downstream sides of the nozzle-feedpipes which enhances turbulence in the gas thereby enhancing mixing ofthe injected sorbent with the gas. The discharge nozzles 70 (FIG. 7) ofthe nozzle-feed pipes are located to inject the discharge 71 of treatingagent into the low pressure zone to better distribute and intermix theinjected treating agent into the surrounding gas stream. The bottom ofbaffle 72 preferably extends below the last nozzle of nozzle-feed pipes52 for a distance approximately equal to the distance between successivedischarge nozzles, whereby due to the flue gas flow patterns in the wakeof the baffle, the excess length of the baffle past the last nozzleserves to distribute additional particles beyond the last dischargenozzle.

As will be better appreciated from the following studies, all of whichwere generated via Computational Fluid Dynamics modeling (CFD), thebaffle 72 acts to markedly enhance gas phase turbulence to therebybetter distribute and mix the injected sorbent particles into thesurrounding gas flow.

The CFD Modeling basis in the studies was as follows:

-   Modeled a pair of vertical lances in a duct partition 9 ft-6 in tall    and 12 ft-6 in wide.-   Total Gas Flow in Duct Partition=396,000 acfm.-   Average Gas Velocity in Duct=55.6 ft/sec-   Gas Temperature=316° F.    Solids Particle Size Distribution for treating agent-   Sauter Mean Diameter=8.5 micron-   Volume Mean Diameter=23.3 micron-   Divided into 6 discrete sizes:

 1 micron 5% by volume  3 micron 5% 11 micron 40%  30 micron 40%  46micron 5% 87 micron 5%

-   Pneumatic Carrier Air Flow per Lance=15 scfm-   Solids Injection Rate per Lance=25.5 lb/hr

Thus in FIG. 8 a schematic broken-away perspective view shows typicalparticle tracks enabled by the prior art apparatus of FIGS. 1 and 1A,where two lances 10 of the prior art type are present in the duct. Thisis to be compared with the FIG. 9 schematic broken-away perspectiveview, which shows typical particle tracks enabled by the apparatus ofthe invention based on two multi-pipe lances 40 of the type depicted inFIGS. 3 through 7 placed side by side in a flue gas duct partition. Itwill be evident that the prior art arrangement results in the ejectedparticles moving downstream in narrow distinct, confined and separatedbands or columns. Increasing the amount of energy used to eject theparticles pushes particles further out from the lance, but still resultsin columns of particles in the gas path. In contrast, the multi-pipelances 40 of the present invention by generating increased gasturbulence and recirculation downstream of the lance, rapidly produce ahighly intermixed and dispersed cloud of particles, and indeed one thatbecomes more spread out and dispersed in the surrounding gas as theparticles proceed in the downstream direction. As mentioned above, anddue to the flue gas flow patterns in the wake of the baffle, the excesslength of the baffle 72 (past the last nozzle as seen at 74) serves todistribute additional sorbent beyond the last discharge nozzle. Thebaffle 72 typically extends below the last nozzle for a distanceapproximately equal to the distance between successive dischargenozzles.

FIGS. 10 and 11, which are each schematic top plan views of the lanceparticle tracks, again show the much greater dispersion achieved by useof the invention lance 40 (FIG. 11) as compared with the use in FIG. 10of the prior art lance 10 of FIGS. 1 and 1A.

The Figures illustrate how the present invention generates a lowpressure zone in the area directly behind (downstream) of the lancebaffle. The feed discharge nozzles 70 in the present invention areplaced within this low pressure zone generated by baffle 72. Positioningthe orifices within the low pressure zone provides the added benefit ofreducing air pressure requirements if the injected particles arepneumatically conveyed. In addition to the low pressure zone, the lancebaffle generates a high-intensity turbulence plume in the gas phaseimmediately downstream of the lance. It is this turbulence plume thatresults in the marked improvement in dispersion of the particulate incomparison to the prior art.

FIGS. 12A through 12F schematically depict cross-sectional views taken10 ft downstream from the prior art lance 10 of FIGS. 1 and 1A, and showdistribution of the total surface area of the ejected particles byparticle size at the said downstream position. This is to be comparedwith FIGS. 13A through 13F which schematically depict cross-sectionalviews taken 10 ft downstream from the multi-pipe lance 40 of theinvention as in FIGS. 3 through 7, and which similarly showsdistribution of the total surface area of the ejected particles byparticle size at the downstream position.

FIG. 14A schematically depicts a cross-sectional view taken 10 ftdownstream from the prior art lance 10 of FIGS. 1 and 1A, and shows thedistribution of the total surface area of the ejected particles of allparticle sizes at the said downstream position. This is to be comparedwith FIG. 14B showing the same cross-sectional view taken 10 ftdownstream from the multi-pipe lance 40 of the invention as in FIGS. 3through 7, and again showing the distribution of the total surface areaof the ejected particles of all particle sizes at the said downstreamposition. The much wider and taller dispersion of particles in the gasstream achieved by the invention will be evident.

The graphical showing of FIG. 15 depicts the normalized pneumaticcarrier air and sorbent surface area distribution along the length of aprior art lance 10 as in FIGS. 1 and 1A, and of a multi-pipe lance 40 ofthe invention. As already mentioned each discharge nozzle has an orificeopening size sufficiently small enough to balance the pressure dropevenly across the exemplified four separate feed pipes. This serves toensure that the pneumatic air and sorbent particles it is conveying areallocated relatively evenly between the separate feed pipes. Themulti-pipe lance 40 (denoted by a black solid line for surface areadistribution and a black solid line with squares for airflowdistribution) is seen to perform better than the simple pipe lance 10because the maximum deviation from 1.0 (where the value 1.0 equates to acompletely even distribution) is less than the simple pipe lance forboth sorbent surface area and air flow distributions.

While the present invention has been set forth in terms of specificembodiments thereof, it will be appreciated that in view of the presentdisclosure, numerous variations upon the invention are now enabled tothose skilled on the art, which variations yet reside within the presentteachings. Accordingly the invention is to be broadly construed, andlimited only by the scope and spirit of the disclosure and of the claimsnow appended hereto.

1. In combination with a fluid treatment system which includes a flowduct in which a fluid stream flowing through the duct is mixed with atreating agent; a dispersion apparatus for dispersing the treating agentinto said fluid stream, comprising: a dispersion lance mounted in saidduct with its axis approximately transverse to the direction of thefluid stream flow, said lance having a treating agent feed section, anda plurality of parallel pipes extending from said section, each saidpipe having one or more feed discharge nozzles along its length forinjecting the treating agent supplied to said pipes into the fluidstream; a baffle extending lengthwise along the upstream side of saidlance, said baffle being of a uniform cross-section along its length,the cross-section having a V or a rounded first portion the convexsurface of which faces upstream of the fluid stream flow; the saidbaffle acting to generate a low pressure zone on the downstream sides ofthe pipes which enhances turbulence in the fluid; and wherein thedischarge nozzles of said pipes are located to inject said treatingagent into the said low pressure zone to better distribute and intermixthe injected treating agent into the surrounding fluid stream.
 2. Acombination in accordance with claim 1, further including generallyflattened wing portions extending from the lateral edges of the saidfirst portion to beyond the sides of the multiple pipes where said wingportions transversely intersect the stream flow
 3. A combination inaccordance with claim 1, wherein said baffle comprises a partialcylinder the convex side of which faces upstream of the fluid streamflow, and with said generally flattened wing portions extending from thelateral edges of the cylinder to beyond the sides of the multiple pipeswhere they transversely intersect the stream flow.
 4. A combination inaccordance with claim 3, wherein said cylinder comprise a semi-cylinder.5. A combination in accordance with claim 4, wherein said fluidcomprises a gas.
 6. A combination in accordance with claim 5 whereinsaid treating agent comprises a particulate.
 7. A combination inaccordance with claim 6, wherein said particulate comprises solidparticles.
 8. A combination in accordance with claim 7, wherein said gascomprises a flue gas, and said particles comprise a sorbent forcomponents of the flue gas which are sought to be removed
 9. Acombination in accordance with claim 7, wherein the said treating agentfeed section includes an inlet supply line and a downstream adjoinedventuri section which acts to redirect treating agent particles awayfrom the walls of the line downstream of any preceding bends in theinlet supply line, the venturi section thereby ameliorating effectscaused by the supply of treating agent not being uniform.
 10. Acombination in accordance with claim 7, wherein the said treating agentfeed section further includes a mixing bar section downstream of theventuri section to generate uniformity in the cross-sectional spread ofthe particle flow proceeding from the mixing bar section.
 11. Acombination in accordance with claim 10, wherein the said treating agentfeed section further includes a splitter vane section for receiving theflow from said mixing bars for allocating the uniformly-distributedparticles from the mixing bars evenly into compartments formed withinthe splitter vane section which lead into and feed the separatenozzle-feed pipes.
 12. A combination in accordance with claim 11,wherein the separate nozzle-feed pipes terminate at differing distancesbelow the said compartments, and wherein the nozzles of each said pipeare at a portion of a said pipe where the nozzle discharges are notimpeded by any of the remaining pipes.
 13. A combination in accordancewith claim 12, wherein the said baffle extends below the last nozzle ofsaid pipes for a distance approximately equal to the distance betweensuccessive discharge nozzles, whereby due to the flue gas flow patternsin the wake of the baffle, the excess length of the baffle past the lastnozzle serves to distribute additional said particles beyond the lastdischarge nozzle.
 14. A combination in accordance with claim 12, whereinthe said feed pipes contain from one to four nozzles.
 15. Thecombination of claim 2, wherein said wings have a generally rectangularshape.
 16. The combination of claim 15, wherein said wings are providedwith notches on their trailing edges.
 17. In a fluid treatment systemwhich includes a flow duct in which a fluid stream flowing through theduct is mixed with a treating agent; a method for dispersing thetreating agent into said fluid stream, comprising: mounting a dispersionlance in said duct with its axis approximately transverse to thedirection of the fluid stream flow, said pipe having a feed section forsaid treating agent and a plurality of parallel pipes extending fromsaid feed section, each said pipe having a series of nozzles along itslength for injecting said treating agent supplied to said pipe into thefluid stream; a baffle extending lengthwise along said lance, saidbaffle being formed as a partial cylinder, the concave side of thecylinder facing upstream of the fluid stream flow; the said baffleacting to generate a low pressure zone on the downstream sides of thepipes which enhances turbulence in the fluid; and wherein the nozzles ofsaid pipes are located to inject said treating agent into the said lowpressure zone to better distribute and intermix the injected treatingagent into the surrounding fluid stream.
 18. A method in accordance withclaim 17, wherein said baffle includes generally flattened wing portionsextending from the lateral edges of the cylinder beyond the sides of themultiple pipes where they transversely intersect the stream flow
 19. Amethod in accordance with claim 17 wherein said fluid comprises a gas.20. A method in accordance with claim 19 wherein said treating agentcomprises a particulate.
 21. A method in accordance with claim 20,wherein said particulate comprises solid particles.
 22. A method inaccordance with claim 21 wherein said gas comprises a flue gas, and saidparticles comprise a sorbent for components of the flue gas sought to beremoved.
 23. A method in accordance with claim 21, wherein said treatingagent comprises a liquid.
 24. A method in accordance with claim 21,wherein said treating agent comprises a gas.
 25. A method in accordancewith claim 17, wherein said fluid comprises a liquid.
 26. A method onaccordance with claim 25, wherein said treating agent comprises aparticulate.
 27. A method in accordance with claim 26, wherein saidparticulate comprises solid particles.
 28. A method in accordance withclaim 25, wherein said treating agent comprises a liquid.
 29. A methodin accordance with claim 25, wherein said treating agent comprises agas.
 30. A method in accordance with claim 18, wherein said wings areprovided with notches on their trailing edges.
 31. In combination with afluid treatment system which includes a flow duct in which a fluidstream flowing through the duct is mixed with a treating agent; adispersion apparatus for dispersing the treating agent into said fluidstream, comprising: a dispersion lance mounted in said duct with itsaxis approximately transverse to the direction of the fluid stream flow,said lance having a plurality of parallel treating agent feed pipes,each said pipe having one or more feed discharge nozzles along itslength for injecting treating agent supplied to said pipes into thefluid stream; feed means for supplying said treating agent to saidpipes; a baffle extending lengthwise along the upstream side of saidlance, said baffle being of a uniform cross-section along its length,the cross-section having a V-shaped or a rounded first portion theconvex surface of which faces upstream of the fluid stream flow; thesaid baffle acting to generate a low pressure zone on the downstreamsides of the pipes which enhances turbulence in the fluid; and whereinthe discharge nozzles of said pipes are located to inject said treatingagent into the said low pressure zone to better distribute and intermixthe injected treating agent into the surrounding fluid stream.
 32. Acombination in accordance with claim 31, wherein the said pipes are fedfrom a common supply at said lance.
 33. A combination in accordance withclaim 31, further including generally flattened wing portions extendingfrom the lateral edges of the said first portion to beyond the sides ofthe multiple pipes where said wing portions transversely intersect thestream flow
 34. A combination in accordance with claim 31, wherein saidbaffle comprises a partial cylinder the convex side of which facesupstream of the fluid stream flow, and with said generally flattenedwing portions extending from the lateral edges of the cylinder to beyondthe sides of the multiple pipes where they transversely intersect thestream flow.
 35. A combination in accordance with claim 34, wherein saidcylinder comprise a semi-cylinder.
 36. A combination in accordance withclaim 31, wherein the said feed pipes each contain from one to fournozzles.